The present invention relates to pressure vessels, particularly to vessels for gas/liquid storage, and more particularly to a lightweight bladder liner which may have high cycle life characteristics for such vessels and to a process for fabrication of same.
Pressure vessels have long been utilized in various applications, particularly for the storage of compressed gas. With the advent of space exploration and the development of ultra-light aircraft, lightweight gas storage vessels have become very important since a significant portion of the weight is in the cylinders used to store the fuel or other gaseous materials. For example, in solar cell/fuel cell powered aircraft, gases generated in an electrolyzer powered by solar cells in daylight are stored and then utilized to provide power for flight at night by combining in a fuel cell. Such a system is described in UCRL-JC-113485, "Regenerative Fuel Cells for High Altitude Long Endurance Solar Powered Aircraft", F. Mitlitsky et al., August 1993. The weight of the gas storage containers is thus a major concern. Similarly, in the case for road vehicles using gaseous fuels and oxidizers, such as hydrogen, oxygen, natural gas, other hydrocarbon gases, and various hydrogen/hydrocarbon gas mixtures, or in other compressed gas storage applications, gas storage vessel weight is a problem. In addition, recent efforts to use compressed gas storage vessels for rechargeable fuel cell powered solar aircraft, road vehicles, lunar/Mars rovers, zero emission vehicles, etc. have illustrated a need for lightweight pressure vessels. Such is discussed in UCRL-JC-117130, "Unitized Regenerative Fuel Cells for Solar Rechargeable Aircraft and Zero Emission Vehicles", F. Mitlitsky et al., Nov. 28, 1994.
The above-mentioned need is satisfied by the present invention which comprises a lightweight bladder lined pressure vessel, that can be utilized for compressed gas storage in applications where vessel weight is limited. The bladder lining of the present invention, compared to the conventional thin wall aluminum vessel barriers or liners and the more recently utilized thick-walled plastic barriers or liners, provides exceptionally high performance factors in weight sensitive applications. The lightweight pressure vessel of the present invention is a polymer lined or metalized polymer lined high strength to weight ratio material, such as graphite epoxy composite, compressed gas storage cylinder, wherein the liner may include a very thin layer of low permeability metal deposited onto a polymeric layer, which is then formed into a cylinder, for example, and provided with end caps.